Along with the ongoing push to reduce the physical size of electrical circuits, there has developed a corresponding need to reduce the space required for mounting electrical components on printed circuit boards (PCBs). Some components, such as resistors, are normally mounted directly onto a PCB. Obviously, the mounting space required of such a component is determined, at least in part, by the component's physical size. Accordingly, the required mounting space of such a component is reduced when the physical size of the component is reduced. Other components, such as a transformer or other electromagnetic device, are held by a frame, which forms an assembly that can then be mounted onto a printed circuit board. These devices typically include windings made of very small gauge wire and are relatively heavy. The mounting frames securely hold the devices to the PCB so as to prevent breakage of the small gauge wires. Accordingly, the required mounting space of transformers and transformers and other electromagnetic devices is determined by the physical size of the device as well as by the physical size of the mounting frame. Reducing the size of the device and/or the frame will reduce the mounting space requirements.
The physical size of an electromagnetic device, such as a transformer, is determined in part by the electrical requirements of the transformer, namely, the voltage, current, and power handling requirements. These requirements may limit how small the transformer can be made. However, reduction in the physical size of such a device is not the subject of the present invention.
As noted above, another way by which the required mounting space of a component, such as a transformer or other electromagnetic device, can be reduced, and which does form the subject of the present invention, is by reducing the physical size of the frame used to mount the component to a PCB. In the case of a transformer, as also noted above, the frame supports the transformer and allows the transformer to be securely mounted to the PCB while, at the same time, protecting the small gauge wires used in the windings of the transformer from breaking. The small gauge wire used in the windings also forms the leads of the transformer. One problem associated with the transformer leads is that, if they are directly connected to the PCB, they may be easily broken due to vibration or other movement of the transformer and/or the PCB. Another problem associated with small gauge transformer leads is that the leads are difficult to insert into mounting holes in the PCB. This difficulty arises, in part, because of the flexibility of the small gauge wire and the corresponding small diameter of the mounting holes.
In order to alleviate the above problems associated with mounting electrical components, such as transformers or other electromagnetic devices to PCBs, the small gauge component leads are usually connected to mounting leads, which are made of larger gauge wire. The mounting leads are then connected to the PCB. One prior art technique connects the component leads to larger gauge mounting leads and encapsulates the component and the component and mounting lead connections. The component and the lead connections are typically encapsulated by placing them in a cup or potting mold which is then filled with a suitable encapsulating material and cured to form an integral assembly. Encapsulating both the component and the component and mounting lead connections increases their resistance to breakage from vibration or other mechanical forces. Unfortunately, this prior art technique produces a rather large and heavy assembly that, in most cases, cannot be supported by the mounting leads. Rather, the bottom of the cup is usually affixed directly to the PCB. The mounting leads exit from the top of the cup and turn down to the PCB where they are soldered in place. One problem associated with this prior art technique is that the cap containing the encapsulated component takes up a significant amount of surface area on the PCB. Not only does the cup take up surface area, but additional space is required for the mounting leads. As a result, this prior art technique for mounting components on PCBs forms a relatively large and heavy assembly that takes up a substantial amount of surface area on a printed circuit board.
Other prior art techniques involve mounting a component to a board, or frame, and connecting the component leads to frame leads attached to the board. Typically, the prior art mounting boards are either flat or have a folded configuration that wraps around the component. The component is, in most cases, glued to the mounting board. The component and mounting board assembly may be encapsulated. In any event, the gluing and/or encapsulating steps are required to securely hold the component to the mounting board. Unfortunately, the gluing and encapsulating steps included in this prior art technique are time consuming and add to the manufacturing cost of the assembly.
As can be appreciated from the foregoing discussion, there has developed a need for an inexpensive mounting device that will securely hold an electrical component, such as a transformer or other electromagnetic device so that it can be attached to a printed circuit board while, at the same time, taking up very little space on the printed circuit board. This invention is directed to a component mounting frame that achieves these results.